1. Technical Field
The present invention relates to an endoscopic device.
2. Related Art
An endoscopic device that is used in the medical field performs a normal observation that observes a subject image almost same as the observation by naked eyes by irradiating white light onto a subject in a biological body as well as a narrow band observation that observes a subject image by irradiating narrow band light having narrower wavelength band than the light irradiated during the normal observation. The narrow band observation observes the blood capillary or a micro pattern of a superficial portion of the mucous membrane in the biological body with a good contrast and helps for an early detection of lesions.
The endoscopic device that is available for the narrow band observation preferably changes the light intensities of the light emitted from the white light and the narrow band light depending on the observation scene. For example, the endoscopic device available for the narrow band observation increases the light intensity of the narrow band light in order to easily observe the blood capillary of the superficial portion of the mucous membrane at the time of near view imaging and increases the light intensity of the white light at the time of distant view imaging to resolve the insufficient amount of irradiated light. By doing this, an observation image suitable for endoscopic diagnosis may be obtained. An endoscopic device that performs the above-mentioned narrow band observation is disclosed in JP-A-2011-10998.
However, when the white light and the narrow band light are irradiated onto the subject while appropriately changing the emitted light intensity ratio of the white light and the narrow band light, the color shade of the illuminating light is changed. As a result, the color tone of the observation image is changed. If the color tone of the observation image is changed, an operator may be bothered by a feeling of strangeness, which may influence an accurate endoscopic diagnosis. Further, if a predetermined image processing is performed to the observation image, an intended image may not be obtained.
In the present invention, an endoscopic device can correct the observation image so that the color tone of the observation image is not changed even though the light intensity ratio of the illuminating light is changed when each illuminating light is emitted from a plurality of light sources that emit light having different spectrums, thereby performing accurate endoscopic diagnosis by observing using illuminating light with an optimal light intensity ratio.